Following an insult to the cornea, the immune and inflammatory systems respond to protect the integrity of the eye. This protective mechanism can have clinical manifestations ranging from cellular infiltration to ulcer formation. Though protective, these processes often compromise the primary function of the eye by causing vascularization, scarring and/or perforation of the cornea.
When there is an insult to the corneal surface, inflammatory and/or immune cells are sent to repair the damage. These cells can aggregate in a region of the cornea and are visible as clinically identifiable infiltrates. This infiltrate formation and resultant corneal inflammation can arise from either infectious or non-infectious conditions. One infectious condition that can adversely affect the cornea is fungal keratitis. Major causes of fungal keratitis in the USA and worldwide include infection by Fusarium and Aspergillus species. In developing countries, fungal keratitis is primarily associated with trauma related to agricultural work; whereas, in industrialized countries, fungal keratitis is associated with contact lens wear.
Currently, steroid use is the only treatment for corneal infiltrates. The side effects of steroid use are considerable. In infectious keratitis, steroids are given only after resolution of infection; otherwise, they can have an adverse effect on the infection. Furthermore, steroid use can cause increased ocular pressure, thereby increasing the risk of glaucoma, and are often administered together with anti-glaucoma treatment.